A mechanical switching device, such as a contactor, a relay, a contact breaker, etcetera, is a remotely operated electric switch used for establishing and disestablishing an electric connection between the gap that separates the conductor members of the pair of conductor members from each other. In case the switching device is used for a three-phase current, the switching device preferably comprises three pairs of conductor members. The conductor bridge is adapted to establishing and disestablishing the electric connection between the conductor ends of the at least one pair of conductor members by means of that the conductor bridge is displaced between the first and the second position. The conductor bridge is displaced by means of that a magnetic field is generated that creates a force that pulls the movable part towards the stationary part.
Switching devices comprise many components, such as base member, conductor members, middle member and switch member, which are assembled together. This is done by means of an attachment arrangement comprising a large number of screw joints. Each conductor member needs to be attached to the base member in a certain position so that an appropriate gap between the conductor ends of the pair of conductor members is formed. Furthermore, the middle member needs to be attached to the base member and the switch member needs to be attached to the middle member.
In order to attach each conductor member to the base member, a switching device requires one screw joint per conductor member. Thus, a switching devices with three pairs of conductor members requires 2×3 screw joints for attaching the conductor members to the base member, at least 4 screw joints for the joining the base member and the middle member and at least 4 screw joints for attaching the switch member to the middle member.
A problem with manufacturing switching devices is that the assembly of the components is time consuming due to the large number of screw joints. Moreover, switching devices need to be disassembled for maintenance and replacement of components after certain period of operation.
U.S. Pat. No. 4,100,517 presents an electrical contactor comprising a base, a pair of fixed contacts separated by a gap, a movable contact and a casing carrying a solenoid. The device further comprises two arms. Each arm is hinged at a first end to the base, wherein the arms are adapted to be pivoted so that a second end of each arm is brought to the casing. The second end of each arm is adapted to be attached to the casing by means of a screw joint so that the components of the contactor are attached together. A problem with the presented electrical contactor is that the two arms increase the complexity and the requirement on dimensional tolerance of the contactor.